Who am I supposed to talk to?

My family is all busy with their own shit. My older brother just moved in to my dad's place because his engagement fell apart. Dad is in Thailand with his wife for the next month. Mum is busy with her cats and her hand dyed yarn business, and my stepdad just doesn't cope well with my depression despite wanting to help. My few friends are so busy with their own lives, working, buying houses, having babies, planning weddings. And my fiancé is so tired of my depression that I genuinely don't believe it would make the slightest difference if I told him any of what I feel aside from annoying him.

I should call a hotline, or maybe one of my professors. I'm in school to become a kindergarten teacher. How am I supposed to teach children when I think like this? I have felt this way since I was a little girl. I'm 25 now. It's not a phase. Pills don't help. Excersize didn't help. My sweet dog is trying but all I can think of when I look at her is that when he leaves me my fiancé is probably going to take her.

I am afraid. I'm alone all the time. People invite me to do things but I'm afraid that if I go anywhere I'll be unable to hold back from telling them. I'm alone and I'm so scared of anyone knowing, but I need help. I just don't want to inconvenience anyone. This has been going on so long without anyone truly taking me seriously, what difference would it really make if I told them I have a plan?